Manufacturing a printhead that has relatively high resolution and print-speed raises a number of problems.
One difficulty is that the likelihood of a faulty nozzle increases linearly with increasing nozzle numbers for a given printhead module. The relatively large number of nozzles in a high-resolution pagewidth printer means that yields can be relatively low compared to smaller printheads for use in scanning inkjet printers. This problem is exacerbated by the fact that the modules used in pagewidth printers are generally larger than those used in scanning inkjet printers. The combination of relatively high failure rate and the greater cost of each failure due to the increased size means that failures in larger modules are relatively more costly than in smaller modules.
Even when nozzles are not faulty in a given module, it may be desirable to provide the ability to print a particular color to a particular dot without relying on a specific nozzle. This may be, for example, in the case where it is desired to output dots at a rate that exceeds the fire rate of a particular nozzle on a printhead module.
It would be desirable to provide a printhead module that offers at least some advantage compared to existing printhead modules, or, at least in the preferred form, allows a given dot to be printed to by more than just one nozzle.